SEMDINLI, Turkey, Nov 11 (AFP) - 17h49 - The Turkish government promised Friday to investigate a deadly bomb attack in this remote southeastern town that has sent tensions in the mainly Kurdish region soaring amid claims security forces may have been involved.

About 10,000 people gathered in Semdinli, in Hakkari province, for the funerals of a man killed in Wednesday's attack against a bookstore, reportedly owned by a former Kurdish guerrilla, and a second person shot dead in ensuing riots.

"Killer state," "Terrorist state," the crowd chanted, also shouting slogans in favor of separatist Kurdish rebels.

Security forces were on high alert as the bodies were brought to Semdinli, near the point where the borders of Turkey, Iran and Iraq meet, after autopsies in Diyarbakir, 630 kilometers (395 miles) to the west.

People using metal power poles dismantled during Thursday's riots erected barricades on several streets to block the expected arrival of police reinforcements from neighboring towns.

In Hakkari city, five people, including a policeman, were wounded in clashes during which police fired warning shots in the air and used tear gas to disperse a crowd outside the mayor's office, the Anatolia news agency reported.

In Ankara, Prime Minister Recep Tayyip Erdogan vowed that those responsible for the blast would be found and punished.

"No one should expect protection or special treatment," he said. "We will not let anyone prepare the ground for confrontation between the state and its people."

Several members of parliament members and some newspapers likened the incident to a major scandal in the 1990s that uncovered links between security forces fighting Kurdish rebels in the southeast, local feudal landlords, politicians and organized crime.

Some members of the security forces were also accused of summary executions, extortion, kidnappings and of smuggling arms and drugs.

The European Court of Human Rights has repeatedly condemned Turkey for human rights violations against Kurdish civilians during the 1984-1999 conflict between armed Kurdish separatists and the Ankara government.

The accusations long remained an obstacle to Turkey's efforts to join the European Union, with which it began membership talks on October 4.

The unrest in Semdinli underscores mounting tensions in Turkey's southeast, where a period of relative calm was shattered last year after the separatist Kurdistan Workers' Party (PKK) called off a five-year unilateral truce.

In a newspaper interview Friday, Semdinli prosecutor Harun Ayik confirmed that a man in police custody, who escaped lynching after allegedly hurling the bomb at the bookstore, was a gendarmerie intelligence agent.

The suspect denied any role in the bombing and said he was attacked by the mob because he was not a local, Ayik told the daily Vatan.

The prosecutor said two non-commissioned gendarmerie officers were also being held as suspects and that a third would be questioned for firing shots in the air during the unrest.

He said weapons and documents found in a car the three suspects allegedly attempted to escape in after the blast did not automatically prove guilt.

Media reports said the documents included a map of Semdinli, a sketch of the bookstore and a list of people, including the store's owner.

Ayik said they did not rule out the possibility that the bombing and the ensuing confusion may have been orchestrated by the PKK to stir up anti-government unrest.

Ankara has sent administrative investigators to look into the incident; a parliamentary commission and ad hoc committees set up by opposition parties are also expected here soon.

Some 37,000 people have been killed since 1984 when the PKK took up arms for Kurdish self-rule in the southeast.

Keen to boost its EU bid, Ankara has recently granted the Kurds a series of cultural freedoms, but Kurdish activists say more should be done to fully mend fences.